1. Field of the Invention
The present invention relates to a back door structure for a motor vehicle, specifically to a back door structure having a stay damper to bias the back door to the open position.
2. Description of the Invention
A motor vehicle with a back door having an opening position and a closing position, including a stay damper to bias the back door to the opening position, is disclosed in Japanese Utility Model Public Disclosure No. 60-124719, filed Jan. 31, 1984, and laid open to the public on Aug. 22, 1985.
The stay damper is disposed between a rear pillar and a frame member of the back door and extends along the rear pillar when the back door is closed. For the motor vehicle described above, it is desired to have a window glass mounted on the back door that has a large area extending outside of the back door frame.
Unfortunately, a difference in level exists between the rear pillar and a side end portion of the window glass because the stay damper is disposed between the back door and the rear pillar. If the window glass would extend outside of the back door frame, the vehicle's appearance would be adversely affected because of this level discrepancy.
Accordingly, it is apparent that in order to improve the vehicle's appearance, an outside portion of the rear pillar needs to be formed outside of a recess for housing the stay damper, arranged high so that the outer portion of the rear pillar comes close to the lower surface of the window glass. However, it is apparent that the back door is constituted wider at its lower portion than at its upper portion. Briefly, the rear pillar which constitutes an inner end portion of a back door opening leans or slants inwardly toward the inner space or front of the vehicle. Therefore, one end of the stay damper connected with the back door will move outwardly in accordance with the movement toward the opening position of the back door.
Accordingly, if the outside portion of the rear pillar which forms an outside boundary of the recess for housing the stay damper is arranged high, the outside portion of the rear pillar will interfere with the stay damper when the back door is opened.